%* *
%*********************************************************
-getImportVersions figures out what the ``usage information'' for this
+mkImportInof figures out what the ``usage information'' for this
moudule is; that is, what it must record in its interface file as the
-things it uses. It records:
-
-\begin{itemize}
-\item (a) anything reachable from its body code
-\item (b) any module exported with a @module Foo@
-\item (c) anything reachable from an exported item
-\end{itemize}
-
-Why (b)? Because if @Foo@ changes then this module's export list
-will change, so we must recompile this module at least as far as
-making a new interface file --- but in practice that means complete
-recompilation.
-
-Why (c)? Consider this:
-\begin{verbatim}
- module A( f, g ) where | module B( f ) where
- import B( f ) | f = h 3
- g = ... | h = ...
-\end{verbatim}
-
-Here, @B.f@ isn't used in A. Should we nevertheless record @B.f@ in
-@A@'s usages? Our idea is that we aren't going to touch A.hi if it is
-*identical* to what it was before. If anything about @B.f@ changes
-than anyone who imports @A@ should be recompiled in case they use
-@B.f@ (they'll get an early exit if they don't). So, if anything
-about @B.f@ changes we'd better make sure that something in A.hi
-changes, and the convenient way to do that is to record the version
-number @B.f@ in A.hi in the usage list. If B.f changes that'll force a
-complete recompiation of A, which is overkill but it's the only way to
-write a new, slightly different, A.hi.
-
-But the example is tricker. Even if @B.f@ doesn't change at all,
-@B.h@ may do so, and this change may not be reflected in @f@'s version
-number. But with -O, a module that imports A must be recompiled if
-@B.h@ changes! So A must record a dependency on @B.h@. So we treat
-the occurrence of @B.f@ in the export list *just as if* it were in the
-code of A, and thereby haul in all the stuff reachable from it.
-
-[NB: If B was compiled with -O, but A isn't, we should really *still*
-haul in all the unfoldings for B, in case the module that imports A *is*
-compiled with -O. I think this is the case.]
-
-Even if B is used at all we get a usage line for B
- import B <n> :: ... ;
-in A.hi, to record the fact that A does import B. This is used to decide
+things it uses.
+
+We produce a line for every module B below the module, A, currently being
+compiled:
+ import B <n> ;
+to record the fact that A does import B indireclty. This is used to decide
to look to look for B.hi rather than B.hi-boot when compiling a module that
imports A. This line says that A imports B, but uses nothing in it.
So we'll get an early bale-out when compiling A if B's version changes.
case rule_decls of
[] -> returnRn decls -- No new rules, so we are done
other -> rnIfaceDecls rnIfaceRuleDecl rule_decls `thenRn` \ rule_decls' ->
- closeDecls (map RuleD rule_decls' ++ decls)
- (plusFVs (map ruleDeclFVs rule_decls'))
+ let
+ rule_fvs = plusFVs (map ruleDeclFVs rule_decls')
+ in
+ traceRn (text "closeRules" <+> ppr rule_decls' $$ fsep (map ppr (nameSetToList rule_fvs))) `thenRn_`
+ closeDecls (map RuleD rule_decls' ++ decls) rule_fvs
+
-------------------------------------------------------
returnRn AlreadySlurped
else
- -- STEP 2: Check if it's already in the type environment
+ -- STEP 2: Check if we've slurped it in while compiling this module
+ getIfacesRn `thenRn` \ ifaces ->
+ if name `elemNameSet` iSlurp ifaces then
+ returnRn AlreadySlurped
+ else
+
+ -- STEP 3: Check if it's already in the type environment
getTypeEnvRn `thenRn` \ lookup ->
case lookup name of {
Just ty_thing | name `elemNameEnv` wiredInThingEnv
Nothing ->
- -- STEP 3: Check if we've slurped it in while compiling this module
- getIfacesRn `thenRn` \ ifaces ->
- if name `elemNameSet` iSlurp ifaces then
- returnRn AlreadySlurped
- else
-
-- STEP 4: OK, we have to slurp it in from an interface file
-- First load the interface file
traceRn nd_doc `thenRn_`
-> ModIface -- Old interface
-> RnMG RecompileRequired
recompileRequired iface_path source_unchanged iface
- = traceRn (text "Considering whether compilation is required for" <+> text iface_path <> colon) `thenRn_`
+ = traceHiDiffsRn (text "Considering whether compilation is required for" <+> text iface_path <> colon) `thenRn_`
-- CHECK WHETHER THE SOURCE HAS CHANGED
if not source_unchanged then
- traceRn (nest 4 (text "Source file changed or recompilation check turned off")) `thenRn_`
+ traceHiDiffsRn (nest 4 (text "Source file changed or recompilation check turned off")) `thenRn_`
returnRn outOfDate
else
| new_vers == old_vers -> returnRn upToDate
| otherwise -> out_of_date (sep [ptext SLIT("Out of date:"), ppr name])
-up_to_date msg = traceRn msg `thenRn_` returnRn upToDate
-out_of_date msg = traceRn msg `thenRn_` returnRn outOfDate
+up_to_date msg = traceHiDiffsRn msg `thenRn_` returnRn upToDate
+out_of_date msg = traceHiDiffsRn msg `thenRn_` returnRn outOfDate
\end{code}
projects / ghc-hetmet.git / blobdiff